American help for Taiwan's military is getting harder to hide, a sign of deeper US involvement that will likely irritate Beijing.

• Reporters ran into crew-cut Western men in plain rain gear near a Taipei subway station during this year's Han Kuang war games, who avoided cameras and slipped away after speaking with a Taiwanese officer.
• These unofficial US advisers are known locally as "English teachers," and Taiwanese media estimate more than 100 were on hand this year.
• The State Department would not confirm any troop presence, repeating that Washington sticks to its one-China policy while supplying what Taiwan needs to defend itself. Taiwan's defense ministry and the Pentagon declined to comment.
• US influence showed up in the drills themselves: Taiwan for the first time used "backbrief," a NATO standard where junior commanders repeat back their understanding of orders so they can act alone if they lose contact with headquarters.
• Analysts say the Americans need to watch in person to judge whether their own training advice is working.

Outlook: As Taiwan adopts more US methods, the American presence will keep growing and become steadily harder to keep quiet.